Stroke, Aphasia
Conditions
Keywords
non-invasive brain stimulation, transcranial alternating current stimulation, neurorehabilitation
Brief summary
This study aims to investigate the efficacy of transcranial alternating current stimulation (tACS) combined with linguistic training for patients with chronic post-stroke aphasia. Thirteen patients will participate in a randomized crossover clinical trial. Their naming ability will be assessed before and after two-weeks of therapy (with 16 days of washout) supported by either 75Hz tACS or sham stimulation. The stimulated cortical area will be selected individually based on the results of functional magnetic resonance imaging.
Detailed description
Aphasia remains one of the most challenging long-term disabilities after stroke. Neuromodulation methods, such as transcranial electrical stimulation, may induce synaptic neuroplasticity processes and facilitate language restoration. Specifically, transcranial alternating current stimulation (tACS) may influence intrinsic cortical oscillations and GABA(A) inhibition. This randomized, triple-blind, within-subject crossover pilot study aims to evaluate the feasibility and efficacy of tACS as an adjunct technique in the therapy of adults with chronic post-stroke aphasia. Participants (\>6 months post-stroke) will undergo 20 therapeutic sessions consisting of language training (with a focus on naming ability) combined with 75 Hz tACS over selected cortical areas. Stimulation targets will be identified individually prior to the first intervention session using functional magnetic resonance imaging (fMRI) during a naming task, selecting regions with the highest BOLD signal. Participants will receive 10 sessions of active tACS and 10 sessions of sham stimulation in randomized order. Each intervention phase will last 2 weeks, resulting a total of 4 weeks of intervention. A 16-day washout period between the two intervention phases will be applied. The language training will include the vanishing cues method and a visual speech perception segment component to support language improvement and maintain a high level of participant motivation. The primary outcome measure will be naming accuracy, assessed as the percentage of correctly named items in a picture-naming task (trained items), measured at three time points: immediately after completion of the intervention (last session), at 2-week, and 6-week follow-up.
Interventions
DEVICEactive 75 Hz transcranial alternating current stimulation
Participants will recive 10 sessions of active tACS. Each session includes 40 minutes (divided into 4 portions with rest breaks in between) of alternating current application in a high gamma frequency range to the language cortex via 5x5 and 5x10 (reference) electrodes.
Participants will recive 10 sessions of sham stimulation. Each session mimics tha active condition, with brief fade-in and fade-out periods (30 seconds) at the beginning and end of each stimulation portion, without delivering a therapeutic dose. Stimualtion is applied over the left hemisphere via 5x5 and 5x10 (reference) electrodes.
Sponsors
QVITI S.A.
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* presence of aphasia (Broca's or mixed) * first ever stroke with one major lesion in left hemisphere * chronic stage (at least 6 months since onset) * right handedness * capability to give an informed consent * Native Polish speaker * 5-80% correct responses in the first naming task
Exclusion criteria
* history of neurosurgical interventions * history of other neurological or psychiatric conditions (including dementia, head trauma, alcohol abuse etc.) * reports of seizures during last 36 months * serious vision disorders * medications increasing risk of seizures or influencing neuroplasticity * electrically, magnetically or mechanically activated implants or other systems sensitive to electricity in the body * history of language and/or speech disorders or intellectual disability in childhood * bilingualism * pregnancy * claustrophobia
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Percentage accuracy in a picture-naming task (trained items) | Assessed immediately after completion of the intervention (last session), at 2-week, and 6-week follow-up | Naming accuracy will be assessed as the percentage of correctly named items in a naming task consisting of 40 realistic pictures of nouns that participants were unable to name correctly prior to the intervention. Score will range from 0% to 100%, where 0% indicates no correct responses and 100% indicates all items named correctly. Higher scores will indicate better naming performance. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Tolerability of electrical stimulation (pain scale) | after each treatment session | Pain intensity will be measured using the Wong-Baker FACES Pain Rating Scale, a validated visual analogue scale ranging from 0 to 10, where 0 indicates "no hurt" and 10 indicates "hurts worst". Higher scores will indicate greater pain intensity, reflect worse tolerability of stimulation. |
| Number of correctly retrieved words at the highest difficulty level (no supporting cues) | during treatment sessions | Naming efficacy will be assessed as the absolute number of correctly retrieved words at the highest difficulty level of the anomia treatment task paired with 75 Hz tACS or sham stimulation. At this level, the target object will be presented without any supporting cues. Higher score will present a better naming performance. |
Countries
Poland
Contacts
PRINCIPAL_INVESTIGATORIwona Sarzyńska-Długosz
Institute of Psychiatry and Neurology
Outcome results
None listed